A defiant President Barack Obama piled pressure on senators Wednesday amid signs his gun reform drive, launched when America was in trauma from the Newtown school massacre, is foundering.
Senators are expected back in Washington next week after a recess and there are clear signs that Obama's hopes of a new ban on assault weapons and curbs on large capacity ammunition clips lack sufficient backing in Congress.
Seeking to regain momentum, Obama traveled to Colorado, a western state with a strong hunting tradition and frontier spirit, which nevertheless passed new gun laws after a mass shooting in a cinema killed 12 people last year.
"I don't believe that weapons designed for theaters of war have any place in movie theaters," Obama said, days after expressing frustration that political momentum was fading as memories of the Newtown school shooting in December ebb.
Obama is now directing his efforts on a plan, opposed by many Republicans, some conservative Democrats and the powerful gun lobby, to require background checks for all gun purchases.
"As soon as next week, every senator will get to vote on whether or not we should require background checks for anyone who wants to purchase a gun," Obama said.
"There is no reason we can't do this, unless politics is getting in the way."
The president said he understood many Americans in rural areas wanted guns for protection or for hunting, and insisted he had no desire to infringe the constitutional rights of "responsible" owners of firearms.
But he lamented delays in Congress over passing new gun control measures following the horror at Sandy Hook elementary school at the end of 2012.
"It's now been just over 100 days since the murder of 20 innocent children and six brave educators in Newtown, Connecticut, an event that shocked this country," Obama said, against a backdrop of police officers in uniform.
"Every day we wait to do something about it, even more of our fellow citizens are stolen from our lives by a bullet from a gun."
Obama scheduled his trip, and another visit to Connecticut next Monday against evidence that plans for gun control legislation are in deep peril.
Wednesday's trip to Colorado took the president to just a few miles from the scene of the mass shooting in the Aurora movie theater last year.
But one of the president's top aides admitted that some in Washington were getting "cold feet" on gun reform, despite national polls showing 90 percent of Americans favor stronger background checks.
"Washington tends to be a lagging indicator of public opinion," Obama senior advisor Dan Pfeiffer said, adding that he remained confident that stronger gun legislation would emerge from the aftermath of Sandy Hook and Aurora.
"What the president wants to sign is the strongest gun bill he can sign," Pfeiffer told a breakfast meeting hosted by the Politico news organization.
"We have to make sure that whatever we do is better than current law. We are going to look at any compromise that comes forward."
Some Republicans, who feel any new laws would infringe on the constitutional right to bear arms, warn they will filibuster legislation expected to be brought up in the Senate next week after Congress returns from recess.
Several Democratic senators, including Mark Pryor of Arkansas, Mary Landrieu of Louisiana and Kay Hagan of North Carolina meanwhile face tough choices that could trap them between their president and conservative constituencies.
Lawmakers in Colorado, which Obama won on the way to re-election in November, have passed new gun laws requiring expanded background checks and limits on the size of magazines for assault weapons.
Opponents of expanding federal background checks argue that they would involve a government registry of firearms which may be unconstitutional.
They also fear that such a scheme would make it tough for family members to hand guns down through generations, or would prove prohibitive in rural areas where people may live many miles from gun stores used to process checks.